Radiative recombination processes in halide perovskites observed by light emission voltage modulated spectroscopy.

The kinetics of light emission in halide perovskite LEDs and solar cells is composed of a radiative recombination of voltage-injected carriers mediated by additional steps such as carrier trapping, redistribution of injected carriers, and photon recycling that affect the observed luminescence decays. We investigate these processes in high performance halide perovskite LEDs, with external quantum efficiency (EQE) and luminance values higher than 20% and 80000 Cd·m -2 , by measuring the frequency-resolved emitted light with respect to modulated voltage, through a new methodology termed light emission voltage modulated spectroscopy (LEVS). We show that the spectra provide detailed information on at least three different characteristic times. Essentially, new information is obtained with respect to the electrical method of impedance spectroscopy (IS), and overall, LEVS shows promise to capture internal kinetics that are difficult to be discerned by other techniques. This article is protected by copyright. All rights reserved.